1. Field of the Invention
This invention relates to a chemical analysis element cartridge in which a plurality of chemical analysis elements each having thereon a reagent layer whose optical density changes by chemical reaction, biochemical reaction, immunoreaction or the like with a specific biochemical or chemical component contained in a sample liquid such as blood or urine are stored and taken out one by one, and more particularly to such a chemical analysis element cartridge provided with a capping member for preventing the chemical analysis elements from slipping out of the cartridge.
2. Description of the Related Art
There have been put into practice various "dry-to-the-touch" chemical analysis elements with which the content of a specific chemical component contained in a sample liquid, the activity thereof, or the content of a solid component can be quantitatively analyzed by only spotting a droplet of the sample liquid on the element. For example, there has been known an integrated multi-layered chemical analysis film. Further a chemical analysis film formed of filter paper and having one or more layers has been proposed and partly put into practice.
When quantitatively analyzing the chemical components or the like contained in a sample liquid using such a chemical analysis film, a droplet of the sample liquid is spotted on the film (on the spreading layer when the film is provided with a spreading layer and directly on the reagent layer when the film is not provided with a spreading layer) and is held at a constant temperature for a predetermined time (incubation) in an incubator so that coloring reaction (coloring matter generating reaction or color change reaction of the coloring substance in the reagent layer) occurs, and the optical density of the color formed by the coloring reaction is optically measured. That is, measuring light containing a wavelength which is preselected according to the combination of the component to be analyzed (sometimes will be referred to as "analyte", hereinbelow) and the reagent contained in the reagent layer of the film is projected onto the film and the optical density of the film is measured. Then the concentration or the activity of the analyte is determined on the basis of the optical density using a calibration curve or a standard curve which represents the relation between the concentration (content) of the analyte and the optical density.
The integrated multi-layered chemical analysis film generally comprises a support sheet of organic polymer and at least one reagent layer formed on the support sheet. Preferably a spreading layer is formed over the reagent layer. The chemical analysis film is generally in the form of a film chip of a predetermined shape such as square or rectangle. The film chip is sometimes provided with a frame of organic polymer or the like for facilitating automated handling of the film chip and sometimes used as it is without frame. The chemical analysis film with a frame is generally referred to as "a chemical analysis slide" and that without frame is generally referred to as "a frameless chemical analysis film".
In this specification, the term "chemical analysis element" should be broadly interpreted to include the frameless chemical analysis film, the chemical analysis slide and the single-layered or multi-layered chemical analysis film formed of filter paper (with or without frame) as well as an electrolyte analysis slide for quantitatively analyzing the activity of particular ionic substances contained in a sample liquid and other like elements and devices for various analyses.
For instance, in Japanese Utility Model Publication 57(1982)-53271 (U.S. Pat. No. 4,151,931), there is disclosed a chemical analysis element cartridge in which a plurality of the chemical analysis elements are stacked and from which the chemical analysis elements are taken out one by one. In the cartridge, a plurality of chemical analysis elements are stacked in a cartridge body which is provided with an element take-out port in a side surface of the upper portion thereof and the uppermost element is pushed out and fed to a chemical analysis apparatus through the element take-out port by a pusher blade which is moved in a horizontal direction. The stack of the elements are supported on a pressing member which is disposed in the cartridge body and is permitted to move only upward by a ratchet mechanism. The pressing member is lifted upward by a plunger inserted into the cartridge body from below so that the stack of the elements is moved upward by a distance equal to the thickness of one element and the second uppermost element is brought to the element take-out port each time the uppermost element is pushed out.
Further there has been known a technique of pressing a stack of chemical analysis elements toward a element take-out port by a pressing member which is urged an elastic body or a spring and taking out the chemical analysis elements one by one through the element take-out port as disclosed, for instance, in Japanese Unexamined Patent Publication Nos. 5(1993)-188058 and 1(1989)-87438 (corresponding to European Patent Laid Open No. 304 838A), European Patent Laid Open No. 567 067A and the like.
However the structures of the cartridge described above is disadvantageous in that when an impact acts on the cartridge during transfer or the like, the chemical analysis elements in the cartridge can move in the cartridge and there is a possibility of the element slipping out of the cartridge through the element take-out port. Further even if the element does not slip out of the cartridge, shift of the position of the elements in the cartridge can adversely affect taking out the elements from the cartridge, transfer of the element and the like, which can result in inaccurate measurement.
That is, when a chemical analysis element projects outside the cartridge, the element can impact against a cartridge holding portion of a biochemical analysis apparatus, which can result in damage on the element or positioning the element in a wrong position. Even if the cartridge can be positioned in place, there is a fear of jam during taking out and transferring the element from the cartridge if the elements are not in the regular place in the cartridge.
Further when the elements are not in the regular place in the cartridge, there is a fear that the sample liquid cannot be spotted in the regular position on the element, which results in ununiform spread of the sample liquid on the element and in deterioration in accuracy of measurement.